We have studied the cw-resolved and time-resolved photoluminescence (PL) spectra of the CdSe quantum dots (QDs), where PL peaks from the "wetting layer" and from the QDs are observed. The temporal behavior of the PL spectra after a short-pulse laser excitation provides evidence of carrier transfer from the wetting layer to the QDs for sufficiently low excitation power and sufficiently high temperature. The dependences of the cw-PL spectra and of PL lifetimes on excitation power are explained by the saturation of the carrier concentration in the QDs as the excitation power increases.
Bibliographical noteFunding Information:
The authors thank M. Dobrowolska for illuminating discussion of the morphology of the CdSe/ZnSe QD system. This work was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MEST) (Grant No. R01-2008-000-20756-0) and the National Science Foundation (Grant No. DMR06-03762).
ASJC Scopus subject areas
- Physics and Astronomy(all)